Gearing assemblies utilizing different types of gearing methods for many different applications are well known in the art. Some applications describe gearing devices that convert in a single stage an input rotation of a shaft, having a relatively high angular velocity and low torque, to an output rotation of another part of the assembly, having a comparatively low angular velocity and high torque. An example of this type of single stage gearing assembly is presented in U.S. Pat. No. 3,955,445 issued Jean-Pierre Osterwalder (hereinafter the “Osterwalder” patent).
The Osterwalder patent describes and illustrates a speed reducing system that can generate a large angular velocity reduction and torque multiplication in a single stage. The system includes an “input shaft” and a separate “output shaft” that is not integral with the input shaft, with the input shaft operatively connected to a gear component having a primary and secondary gear which rotate as a single gear. The primary gear engages a fixed gear spline, while the secondary gear engages a rotatable output gear spline. The Osterwalder patent states that this combination of gears, together with an eccentric and counterweight integral with the input shaft, provides a system with numerous advantages in the field of high-ratio mechanical power transmission. More specifically, the patent describes that in order to “achieve a dynamically balance system” an eccentric, utilized to create an eccentric rotational motion of the primary and secondary gears, is “formed integrally with a “counterweight” that functions to balance the system. The Osterwalder patent also describes a nonrotatable input gear spline and a rotatable output gear spline, with the rotatable output gear spline integral with an output shaft, also referred to as an “output transmitting member”, and with the peripheral, outside diameter of the output transmitting member journaled for rotation by a relatively large diameter bearing assembly with an outer casing forming part of the external structure of the system. In this regard, it is again noted that the output shaft, also referred to as the output transmitting member, is not integral with or part of the input shaft. In operation, the rotating input shaft imparts an eccentric rotation to the primary and secondary gears, with the engagement of the secondary gear with the rotatable output gear spline causing the output transmitting member to rotate at a high torque much higher than the torque of the input shaft. In this regard, although not expressly discussed in the Osterwalder patent, it is pointed out that the large diameter bearing assembly might also contribute to dynamic instability of the system, necessitating the use of the counterweight. Another significant limitation of the gearing assembly disclosed by the Osterwalder patent is that the assembly can only generate the single function of imparting a rotational motion to the output transmitting member. It is a feature of the dual function gearbox disclosed herein that the gearbox overcomes the limitations of the system disclosed in the Osterwalder patent.
There are several applications for using a single gearbox that can generate as an output a high torque that can be used to rotate a long row of devices. One example would be a conventional solar tracker that rotates a long array of solar panels in order for the panels to follow the apparent path of the sun, thereby maximizing the amount of sunlight that is absorbed by the solar panels. In this regard, the conventional method normally uses a single motor and associated gearbox to rotate a long torque tube that rotates the solar panel row. Depending on the number of solar panels in the row, the motor may need to generate an extremely high torque in order to impart sufficient torque to the torque tube to successfully overcome the torque generated by wind loads on the solar panels. In this regard, since a single motor is normally used for a row, or maybe used for multiple rows, the torques tubes need to be long, in some cases up to 300 feet or more. And, long torque tubes will develop large torsional deflections and are vulnerable to premature failure due to the torsional loads, low frequency vibration due to torsional loads, and thermal expansion axially through the torque tubes. Another application that utilizes similar technology are greenhouses that need to open and close rows of glass windows, not necessarily in linear alignment, in order to regulate the temperate in the greenhouse.
An object of the present dual function gearbox, gearbox system and method is to provide a new and improved gearbox that generates dual rotational output motions from a single gearbox or from a system of gearboxes to control solar panels, greenhouse windows and other similar applications.